Disk drives using various kinds of disks, such as optical disks, magneto-optical disks, flexible magnetic-recording disks, and similar information-storage disks are known in the art. In particular, hard disk drives (HDDs) have been widely used as information-storage devices that are indispensable for contemporary computer systems. Moreover, HDDs have found widespread application to motion picture recording and reproducing apparatuses, car navigation systems, cellular phones, and similar devices, in addition to computers, because of the outstanding information-storage characteristics of HDDs.
Magnetic-recording disks used in HDDs have multiple concentric data tracks and servo tracks. Each servo track includes multiple servo data areas, some including address information. Each data track includes multiple data sectors including user data. Data sectors are recorded discretely in the circumferential direction between servo data areas. A magnetic-recording head of a head-slider supported by a rotary actuator accesses a desired data sector in accordance with address information provided by servo data to write data to, or read data from, the data sector. A head-slider is bonded on a suspension of the actuator. The pressure caused by air viscosity between an air bearing surface (ABS) of the head-slider facing a magnetic-recording disk and the spinning magnetic-recording disk balances the pressure applied by the suspension toward the magnetic-recording disk so that the head-slider flies above the magnetic-recording disk with a certain fly height. The actuator rotates on a pivot shaft to move the head-slider to a target data track and positions the head-slider above the track.
An HDD accesses data on a magnetic-recording disk in units of data sectors. In a typical HDD, the size of a data sector is 512 bytes. Hence, most contemporary computer programs, also referred to herein by the term of art, “hosts,” are written based on the data sector size of 512 bytes. However, with the advance of software technology, the data size handled by software is increasing; consequently, the data size for the unit of access by an HDD is likely to correspondingly increase. For example, a data sector size of 4 kilobytes (4096 bytes) has been proposed. Increasing the data sector size for the unit of access reduces additional redundant data relative to data stored in a 512-byte sector that is present in addition to user data; and, consequently, increasing the data sector size is expected to increase the capacity of a recording surface of a magnetic-recording disk because of more economical use of the space for the recording of information on the recording surface.
Non-uniformity of data sector size in programs, hosts, raises the issue of adjusting the HDDs' data sector size. Even if large-sized data sectors become widely used, not all software, hosts, may readily be written based on the large-sized data sectors; and, it is expected that some software will be written based on the conventional 512-byte data sectors. In addition, users, in practice, use both new programs and old programs. Accordingly, it is desirable that HDDs support both the conventional 512-byte data sectors, as well as the new large-sized data sectors.